Treatment of effluent from fertilizer industry by adsorption on willow sawdust-removal of Ni(II) and Cd(II) from the effluent

Sawdust of willow has been investigated as an adsorbent for the removal of Ni(II), and Cd(II) ions from aqueous solution. Since willow tree is widely grown in almost all parts of Kashmir, it can be a common most easily available, sustainable, low cost adsorbent for the treatment of wastewaters in this part of the world where growing industrialization is affecting water quality like elsewhere in the world. Therefore, it is worthwhile to investigate the potential of sawdust of willow tree as an adsorbent for the removal of Ni(II) and Cd(II) ions from aqueous solution as a first step. Batch experiments were conducted to study the effect of some parameters such as contact time, initial concentration of metal ions, solution pH and temperature. Langmuir and Freundlich models were employed for the mechanistic analysis of experimental data obtained. Results reveal that in our system adsorption follows the Langmuir isotherm. The maximum adsorption capacity of Ni(II) and Cd(II) were found to be 7.98 and 7.11 mg/g respectively at optimum conditions. The pseudo-first-order and pseudo-second-order models were employed for kinetic analysis of adsorption process. The adsorption process follows pseudo-second-order kinetics. The efficacy of the adsorbent in the treatment of effluent from fertilizer factory has been investigated and the results have been found encouraging.

Selective Sorption of Ge(IV) Oxoanion by Composite Sorbent Based on Hydrous Oxide of Zirconium

In this work, a composite sorbent based on hydrous zirconium oxide was used for selective removal of Ge(IV) oxoanions. Experiments were carried out by batch equilibrium tests and dynamic column sorption. The best sorption capacity was reached at the pH of 9, when about 4.3 g of Ge by liter of composite. The negative effect of the concentration of chlorides and sulfates was observed when their concentration was higher than 500 mg/L. The optimal specific solution flow rate for sorption by ZrO2-PAN sorbent was determined to be 6 BV/h. For regeneration, 15 BV of 0.5 M HCl solution saturated with NaCl was used.

Removal of arsenic from aqueous solution containing hexafluoroarsenate

Arsenic removal from aqueous solutions containing hexafluoroarsenate or arsenate by strong and weak base anion exchangers was studied by dynamic column tests that were carried out using solution containing arsenic and accompanying anions (chlorides, sulfates and fluorides). The specific flow rate of solution was 6 BV/h. Desorption of arsenic was carried out by 1 mol/L NaOH or 2 mol/L KSCN. All the studied anion exchangers performed well in the absence of accompanying anions. In the presence of chlorides and sulfates, studied exchangers showed high selectivity towards hexafluoroarsenate.

Sorption of Se (IV) and (VI) oxyanions from aqueous solutions

Different types of sorbents were tested to selectively remove oxyanions of SeIV and SeVI from model solutions containing various accompanying anions (chlorides, nitrates, sulphates) that simulate real conditions and may affect the sorption of selenium oxyanions. In addition to the optimization of sorption conditions. The best results of selenite sorption were achieved with sorbent GEH (hydrated iron oxide sorbent) and selenate sorption with Purolite S110 (N-methylglucamine functional group). The optimal pH for sorption of SeIV using GEH was found to be 3 and for sorption of SeVI it was pH 4.